1. Field of the Invention
The present invention relates to a noise filter with an inlet socket. More specifically, the present invention relates to a noise filter with an inlet socket for removing high frequency noise components from a switching power supply and the like.
2. Description of the Prior Art
One example of a conventional noise filter with inlet socket is disclosed, for example, in Japanese Utility Model Laid Open No. 134820/1981 laid open on Oct. 13, 1981. In addition, mounting structures for such a conventional noise filter are generally shown in FIGS. 9A, 9B, 10A and 10B.
In the example shown in FIGS. 9A and 9B, the noise filter with inlet socket 10 is mounted from a front side of a chassis 12 of an apparatus. In the example of FIGS. 10A and 10B, the noise filter with inlet socket 10 is mounted from a rear side of a chassis 12 of an apparatus.
In general, bolts and nuts are used to secure the noise filter 10 onto the chassis 12. In such case the electric stability of the earth (ground) is deemed to be sufficient.
In either example of FIGS. 9A, 9B and 10A, 10B, however, when the chassis 12 is coated with paint, the ground connection becomes very unstable due to the coated layer 12a, and the earth portion which is to be connected to the ground potential is likely to isolated from the ground potential in the worst case.
In order to avoid such unstable grounding, an earth terminal is used and is connected to the ground potential with a lead wire, but in such case, the grounding will become unstable against high frequency noise components due to the unductance of the lead wire.